Process and apparatus for producing torque in synthetic filaments,fibers and yarns



April 1, 1969 I c M. we 3,435,603 I PROCESS AND APPARATLIS FOR PRODUCING TORQUE IN SYNTHETIC FILAMENTS, FIBERS AND YARNS Filed Oct. 60, 1967 Sheet of 3 TWIST- HEAT SET ZONE INVENTOR.

CHARLES M. R I CE c. M. RICE 3, PROCESS AND APPARATUS FOR PRODUCING TORQUE IN SYNTHETIC FILAMENTS, FIBERS AND YARNS Filed Oct. 30. 1967 Sheet 2 of 3 April 1, 1969 TWIST DRAW- HEAT SET ZONE INVENTOR- CHARLES M. RICE BY Apnl 1, 1969' c. M. RICE 3,435,603

' PROCESS AND APPARATUS FOR vPRODUCING TORQUE IN SYNTHETIC FILAMENTS, FIBERS AND Y'ARNS Filed Got. 50, 1967 Sheet 3 of s INVENTOR CHARLES M. RICE United States Patent 3,435,603 PROCESS AND APPARATUS FOR PRODUCING TORQUE IN SYNTHETIC FILAMENTS, FIBERS AND YARNS Charles M. Rice, Chandler, N.C., assignor to American Enka Corporation, Enka, N.C., a corporation of Delaware Filed Oct. 30, 1967, Ser. No. 678,807 Int. Cl. Dtllh 13/28, 7/92, 7/46 US. CI. 5734 9 Claims ABSTRACT OF THE DISCLOSURE Process and apparatus for imparting torque to a continuous synthetic filament, strand or yarn end comprising forwarding the yarn to a heat setting means, thence to a zone Where the yarn is wrapped one or more turns about itself, and finally to a device for collecting the yarn in package form; the yarn, while under forwarding tension and being wound on itself, translates twist about its own longitudinal axis which can be set by heating and subsequent cooling.

This invention relates generally to an apparatus and method for producing torque in heat settable continuous thermoplastic monofilaments, strands and/ or yarns. More specifically, the present invention relates to improvements in an apparatus for and a method of producing a high degree of torque-twist (twist along its longitudinal axis) in synthetic filaments, strands, and yarns such as those produced from synthetic polyamides, polyesters and the like which advantageously may be adopted by yarn producers as distinguished from crimping or twisting methods using plural steps starting with previously oriented, prepackaged filaments and yarns.

US. patent application Ser. No. 395,997 filed Sept. 14, 1964, to Virginia S. Bowers et al. discloses a commercially acceptable process which permits inserting useful torquetwist in freshly drawn synthetic yarns. The process of the application visualizes imparting strong torsional forces in synthetic monofilaments, strands and/or yarns utilizing a continuous one-step process by stripping back and heat setting a false twist imparted during traveller rotation on a conventional drawtwisting machine. This process produces a uniform torque-twist in a yarn with each filament thereof having torsional forces favorably comparable to that obtainable when using the more expensive, multistep, conventional false twisting procedures wherein a false twist spindle is used, starting with yarn produced and packaged by synthetic yarn producers. In complete contradistinction to the process visualized in the pending application, or in those using false twisting procedures, the instant application is concerned with an improved torque twisting method and apparatus wherein a false twist is imparted to a filament or yarn which has been wound on itself and, as one embodiment, while being drawn (molecularly oriented).

It is known to false twist filaments and yarns while drawing, as exemplified by British Patent No. 815,202. It is important to note, however, that the patent teaches imparting the twist using a mechanical false twisting device which severely restricts processing speeds due to the limiting factors of friction, centrifugal force and the like, although the process of the patent as well as other known types of torque-producing methods are used by the synthetic yarn manufacturers to effectively compete pricewise with those processes wherein stretch yarn is produced by the discontinuous false twisting methods whereby drawn yarn is still texturized in more or less a step-bystep operation. This certainly is understadable when one 3,435,603 Patented Apr. 1, 1969 "ice considers the fact that increased savings are realized by yarn producers in packaging, storing, transportation and the like. Accordingly, various known processes and apparatus are often tried and sometimes utilized by yarn producers on conventional equipment, that is, equipment such as drawtwisters and the like, in order to manufacture torque-twisted yarns even though the merchandise obtained therefrom often has a reduced elasticity, strength and, in general, poor quality, and notwithstanding the fact that the modified equipment is often expensive to operate and maintain.

It is also known that thread can be deformed 'by being wound on itself. US. Patent 2,881,504 to Billion shows that a single end, passing through a series of guides and rollers, can be wound back across itself and accordingly curled and set by heat in the same zone in which the twist occurs. This procedure, in effect, captures the deformations or, more precisely, the curls imparted and heat set in the patents so-called treatment zone by continuously passing the thread around itself. As set out more in detail below, filaments, strands, threads or synonomously, yarn, by being repeatedly wound back on themselves surprisingly are twisted about their longitudinal axis upstream of the area where they are wound. In complete contradistinction to known processes of producing stretch yarn of the helical or coiled type, the present application employs the method of heat setting and thereafter cooling the twist which occurs upstream of a locus where the filaments or yarns are wound together, with the result that the yarn produced thereby has torque-twist but is substantially free of any tendency to curl into a helical shape.

It is therefore the chief aim of this invention to provide a process and apparatus for preparing synthetic filaments and yarns having torque and which are of excellent quality in regard to their torque strength, recovery power, uniformity and the like.

It is a further object of this invention to provide a process and apparatus whereby yarn may be cold or hot drawn, twisted about its longitudinal axis, and simultaneously heat set in a single, rapid and continuous operation.

It is still another object of this invention to provide a process for producing fialments and yarn having torque wherein the essential twisting-producing component is a single end twisted upon itself or multiple ends twisted together.

It is also an important object to provide a simplified and relatively inexpenesive process and apparatus for producing torque in single or plural ends of a heat settable thermoplastic yarn while drawing.

Finally, it is an important object of this invention to provide a spindle apparatus of novel construction for initially winding the yarn or strand on itself.

In brief, these and other objectives are accomplished according to the invention by an improved method and apparatus wherein a continuous synthetic filament or yarn from a suitable source is led to a heat setting zone, thence one or more helical wraps about itself, followed by collecting the filament or yarn conventionally in package form. The yarn, while under forwarding tension and being wound on itself, translates twist about its longitudinal axis and is heated upstream of the locus where it is wound on itself to cause molecular reorientation to take place while in the twisted state. Subsequent cooling serves to set the reoriented molecules in the condition of applied stress. In one embodiment, a torque yarn is prepared by subjecting the yarn while drawing to the torqueing and heating steps of the invention.

According to the invention, the term torque-twisting or simply torqueing refers to an effect produced by twsting the yarn to a high degree about its longitudinal axis, heat setting the yarn, and then removing the twist, using the instant process and apparatus and in contradistinction to curling the yarn in order to obtain a threedimensional curvilinear yarn as described in Carruthers patent (US. No. 3,091,908) and others. Although not readily ascertainable by visual examination, the yarn will, when relaxed and therefore under conditions of minimum restraint, attempt to assume the shape in which it was heat set and subsequently cooled. Therefore, the term torque or torsional force for the purposes of the invention is that force which causes the filaments to attempt to twist about their axis owing to their previous physical and thermal treatment. Heat setting means heating the thermoplastic yarn to an elevated temperature which in turn rearranges or reorients the internal molecular structure thereof while in this configuration. Rearranging the molecules by an application of suitable heat, followed immediately by cooling and removal of twist, causes the filaments to attempt to return to the twisted configuration.

The filaments and yarn applicable to the invention are those composed of thermoplastic synthetic polymeric compositions and preferably consist of the various polyamides and polyesters, such as poly(hexamethylene adipamide), poly(epsilon caprolactam), poly(ethylene terephthalate), including mixtures and structural composites composed of two or more longitudinally extending segments of different polymers. The invention is particularly applicable to continuous filaments, yarns, and similar strands spun from these polymers. Continuous strands, whether a monofilament or as plural filaments, are suitable.

The invention can be described most effectively by reference to the accompanying drawings wherein:

FIGURE 1 is a schematic perspective view of preferred apparatus arranged for processing the torque yarn according to the invention which is particularly adapted for drawing (molecularly orienting) the yarn followed by imparting torque by pulling the yarn around itself.

FIGURE 2 is also a perspective representation of an embodiment wherein torque is imparted by forwarding the yarn about itself and by drawing the yarn in the zone into which the resulting torque-twist is translated.

FIGURE 3 illustrates, inter alia, the spindle apparatus for initially arranged the strand or yarn end with respect to its being wound or twisted repeatedly about itself and in a manner which will prevent its shifting during constant running in a given path.

FIGURE 4 shows a frontal view of a yarn end being twisted about itself using the apparatus of this invention.

The invention comprises other features of construction, combination of elements and arrangements of parts which will be exemplified in the ensuing detailed description, the scope of the invention being indicated solely by the claims.

Referring generally to FIGURE 1, yarn end is supplied from a suitable source 1, illustrated as a producers spin package. The undrawn yarn is removed end over end from the package by way of pigtail guide means 2 and roller guide 3 onto auxiliary cot 4a and roll 4. The end is wound around cot 4a several times and thence to roll 4. Both cot 4a and roll 4 constitute the yarn feeding means and are driven by appropriate shafts not shown. The yarn end is supplied in an under-and-over arrangement to draw pins 5, and thence to and about draw roll 6 and cooperating separator roll 7. The feed and draw rolls are driven at predetermined speeds. The yarn is drawn between feed roll 4 and draw roll 6 which operates at a higher peripheral speed than the speed at which the yarn is supplied. Localization of draw or necking down occurs at pin 5. After one or more wraps around draw roll 6 and associated separator roll 7, the yarn passes over freely rotatable roll 7a, roller guide 8, thence to heated plate 9. Thereafter the yarn passes through a slot in a device of construction for initially imparting twist or winding the yarn about or across itself; it is then wrapped one or more times about draw roll 6 and the associated roll 7. After this second pass around the draw roll, the yarn passes over freely rotatable roll 7!), and then it again enters the slot provided in the twist-imparting spindle 10 and parallel to the same end, previously positioned in the manner set forth above. From the twistimparting device, the yarn encounters the draw and separator rolls for the third time and is thereafter wound in a conventional manner by ring and traveler 13 onto package 14.

As indicated hereinabove, the yarn path is parallel during initial thread-up when positioned in twist-imparting spindle 10 (see FIGURE 3). After the yarn passes the previously laid strand (end) and is fed one or more times around the drawn roll and to the ring and traveler onto package 14, spindle 10 is rotated manually to insert one or more turns of twist. The direction in which the device is rotated (and, accordingly, the direction in which the parallel strands are wound) determines the direction of twist (S or Z) which is imparted upstream of ,the device. It is important to note that twist-imparting spindle 10 is not adapted for continuous rotation while the yarn is running; it is utilized merely to initially wind (or, synonomously for the purpose of this aspect of the invention, twist) the yarn about itself; the twist will, in turn, impart a turning or twisting moment about the longitudinal axis of the strand upstream of where it is wound.

Experimental results indicate that the amount of heat settable twist obtainable depends directly on the angle at which the yarn enters the twist zone (FIGURES 3 and 4). An angle of between 10 and about 30 between the yarn ends where they converge about separator rod 16 is preferred.

A somewhat different embodiment is shown in FIG- URE 2. In this illustration, the yarn end being fed by roll 4 and cooperating cot 4a passes over (or alternatively, around) draw pin 15 and is preplasticized by heated plate 9. The yarn path following draw pin 15 and extending,

over heated plate 9 is considered as the drawing and twisting zone. From pin 15, the yarn is passed through a slot provided in spindle 10 (FIGURE 3) and then one or more wraps around the draw roll and its associated freely rotatable separator roll 7 before passing over freely rotatable roll 7b and back through spindle 10. The yarn is positioned in spindle 10 parallel to the strand previously laid before the device is rotated to cause travel of the yarn around or about itself. In fact, therefore, the strand is positioned parallel to itself before being wound by spindle 10.

The heater plate is heated to that temperature which sufficiently softens the yarn but which does not cause fusion or degradation thereof. It has been observed that most effective plasticizing is accomplished by heating the yarn to or slightly above its second-order transition temperature and is usually achieved empirically depending on the yarn denier, yarn speed, path of exposure across the plate, and of course, the temperature of the plate.

As discussed briefly above, the apparatus is set up for the purpose of arranging the yarn end parallel when passing through twist spindle 10 wherein it is pretwisted or wound around itself by an operator. Any desired number of turns in either direction, i.e., clockwise or counterclockwise, may be imparted. As will be appreciated when referring to FIGURES 3 and 4, the yarn or strand 20 is placed in the spindle bore through yarn-receiving slot 28 and is positioned on each side of yarn guide and twist imparting pin 18. An operator inserts a flexible plastic rod of suitable length and diameter into cutaway segment 30, presses it against serrations 32, and pulls it sideward, thereby rotating spindle 10 any desired number of turns. Serrations 32 are provided in the outer cylindrical wall of the spindle to facilitate its grip upon the plastic rod. Yarn deflecting protuberances 24 on each side of slot 28 serve to position the parallel strands in the spindle bore and to prevent their popping out when under tension before or during twisting. Wire spring 22 serves to restrain the spindle in the manner shown in order that it will stop in the proper position and will not rotate inadvertently. Separator rod 16 arranges yarn travel to spindle and is positioned in a manner to keep the ends separate.

The twist introduced to yarn 20 upstream of the twist zone above pin 18 will be recognized as a false twist. The twist is imparted to the yarn by passing an end thereof about itself and is set into the yarn in the heating and cooling zone located upstream of separator rod 16 (FIG- URE 3).

Obviously, a second zone of opposite twist is also created below pin 18. This twist, however, as shown by FIGURE 4, produces no significant effect because the twist is made to be more loose by spreading the turns over a greater length.

Having described the invention, what is claimed as new and desired to protect by Letters Patent is:

1. A process for the production of torque in a continuous synthetic filament, strand or yarn comprising in combination:

(a) forwarding the filament, strand or yarn to a winding zone,

(b) winding the filament, strand or yarn one or more helical wraps about itself to translate twist about its longitudinal axis upstream of the zone of where it is wound,

(c) heat setting and subsequently cooling the twist thus imparted upstream and, thereafter,

(d) collecting the filament, strand or yarn in package form.

2. A process for the production of torque in a continuous synthetic filament, strand or yarn comprising in combination:

(a) winding undrawn filament, strand or yarn one or more helical wraps about itself to translate twist about its longitudinal axis upstream of zone of where it is wound,

(b) simultaneously drawing the filament, strand or (c) heat setting the imparted twist upstream, and

(d) collecting the filament, strand or yarn in package form.

3. Apparatus for imparting one or more helical wraps to a single end of a filament, strand or yarn comprising:

(a) a tubular spindle mounted in a supporting means and adapted for rotation therein,

(b) a filament, strand or yarn receiving slot extending longitudinally in said spindle and passing through to an axial bore thereof,

(c) a filament, strand or yarn guide and twist imparting member secured to at least one cylindrical inner wall of said spindle, and

(d) a filament, strand or yarn deflecting means pro vided on each side of said yarn receiving slot.

4. Apparatus for twisting continuous filaments, strands or yarns comprising:

(a) a tubular spindle mounted in a supporting means and adapted for rotation therein,

(b) a filament, strand or yarn receiving slot extending longitudinally in said spindle and passing through to an axial bore thereof,

(c) a filament, strand or yarn guide and twist imparting member secured to at least one cylindrical inner wall of said spindle, and

(d) means to releasably lock said tubular spindle against rotation.

5. The process as set forth in claim 1 wherein the filament, strand or yarn is forwarded to a zone providing one or more helical wraps thereto and at an angle of between 10 to 30 degrees with respect to a segment of itself and about which the synthetic filament, strand or yarn is wound.

6. The process as set forth in claim 2 wherein the filament, strand or yarn is forwarded to a zone providing one or more helical warps thereto and at an angle of between 10 to 30 degrees with respect to a segment of itself and about which the synthetic filament, strand or yarn is wound.

7. Apparatus as set forth in claim 4 wherein a filament, strand or yarn deflecting means is provided on each side of said yarn receiving slot.

8. A torque filament, strand or yarn produced by the process of claim 1.

9. A torque filament, strand or yarn produced by the process of claim 2.

References Cited UNITED STATES PATENTS 2,881,504 4/1959 Billion 28-72 2,963,848 12/1960 Finlayson et al. 5734 2,991,614 7/1961 Ubbelohde 57-34 3,028,654 4/ 1962 Evans 57--34 XR 3,035,396 5/1962 Biggers 57-34 3,148,520 9/1964 Biggers 28-72 XR 3,355,872 12/ 1967 Gilcrist et a1 5734 XR DONALD E. WATKINS, Primary Examiner.

US. Cl. X.R. 

